Line of Credit Facility, Covenant Terms, Default Provision, Maximum Indebtedness

No definition available.

Name:	aee_LineOfCreditFacilityCovenantTermsDefaultProvisionMaximumIndebtedness
Namespace Prefix:	aee_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Line Of Credit Facility Maximum Borrowing Capacity Per Lender

+ References

No definition available.

+ Details

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Namespace Prefix:	aee_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The net liquidity available is based on credit facility borrowings, commercial paper outstanding, and letters of credit issued under the Credit Agreements, along with cash and cash equivalents.

+ References

No definition available.

+ Details

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Namespace Prefix:	aee_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Number Of Lenders

+ References

No definition available.

+ Details

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Namespace Prefix:	aee_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Short Term Debt, Weighted Average Interest Rate During Period

+ References

No definition available.

+ Details

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Namespace Prefix:	aee_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

The total amount of the contingent obligation under letters of credit outstanding as of the reporting date.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 944
-SubTopic 605
-Name Accounting Standards Codification
-Section 55
-Paragraph 15
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477548/944-605-55-15

Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Topic 944
-SubTopic 605
-Name Accounting Standards Codification
-Section 55
-Paragraph 12
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477548/944-605-55-12

+ Details

Name:	us-gaap_LettersOfCreditOutstandingAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22)(b))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(19)(b))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Indebtedness divided by net capital.

+ References

No definition available.

+ Details

Name:	us-gaap_RatioOfIndebtednessToNetCapital1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	instant

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

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Balance Type:	na
Period Type:	duration

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- Details

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Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=aee_MultiyearCreditFacilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MaximumMember
Namespace Prefix:
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- Details

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- Details

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- Details

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- Details

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Short-Term Debt And Liquidity (Narrative) (Details)	12 Months Ended
Short-Term Debt And Liquidity (Narrative) (Details)	Dec. 31, 2025 USD ($) lender	Dec. 31, 2024
Utilities
Short-term Debt [Line Items]
Average interest rate	4.39%	5.19%
Multiyear Credit Facility
Short-term Debt [Line Items]
Number of lenders \| lender	20
Line of credit facility, maximum borrowing capacity, per lender	$ 208,000,000
Multiyear Credit Facility
Short-term Debt [Line Items]
Line of credit facility, maximum borrowing capacity	3,200,000,000
Commitment fee amount	$ 120,000,000
Actual debt-to-capital ratio	0.59
Multiyear Credit Facility \| Maximum
Short-term Debt [Line Items]
Actual debt-to-capital ratio	0.675
Multiyear Credit Facility \| Maximum \| Ameren Missouri
Short-term Debt [Line Items]
Actual debt-to-capital ratio	0.65
Multiyear Credit Facility \| Maximum \| Ameren Illinois
Short-term Debt [Line Items]
Actual debt-to-capital ratio	0.65
Missouri Credit Agreement
Short-term Debt [Line Items]
Line of credit facility, maximum borrowing capacity	$ 1,900,000,000
Missouri Credit Agreement \| Ameren Missouri
Short-term Debt [Line Items]
Line of credit facility, maximum borrowing capacity	$ 1,600,000,000
Actual debt-to-capital ratio	0.49
Missouri Credit Agreement \| Multiyear Credit Facility
Short-term Debt [Line Items]
Line of credit facility, maximum borrowing capacity	$ 2,400,000,000
Illinois Credit Agreement
Short-term Debt [Line Items]
Line of credit facility, maximum borrowing capacity	1,300,000,000
Illinois Credit Agreement \| Ameren Illinois
Short-term Debt [Line Items]
Line of credit facility, maximum borrowing capacity	$ 1,100,000,000
Actual debt-to-capital ratio	0.45
Illinois Credit Agreement \| Multiyear Credit Facility
Short-term Debt [Line Items]
Line of credit facility, maximum borrowing capacity	$ 1,600,000,000
Credit Agreements
Short-term Debt [Line Items]
Commitment fee amount	33,000,000
Net liquidity available	2,500,000,000
Covenant terms, default provisions, maximum indebtedness	$ 150,000,000